Distillation of wax materials



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Aug. 8, 1933. w, H. BAHLKE DIsTILLATIoN oF wAx MATERIALS Filed Oct. 5. 1929 Patented Aug. 8, 1933 UNITED STATES- nrs'rILLATIoN oF WAX MATERIALS William H. Bahlke,

Hammond, Ind., assignor to Standard Oil Company, Whiting, Ind., a Corporation of Indiana Application Gctober 5, 1929. Serial No. 397,535

8 Claims.

tion of high melt-point waxes and more particularly to their production from lower melt-point waxes, crude scale wax and the like by a distillation process. The invention will be readily understood from the following description, i1- lustrated by the accompany drawing, in which apparatus is shown diagrammatically, and partly in section, suitable for carrying out the invention.

10 Referring to the drawing, 10 is a heating coil located in a setting 11, provided with suitable heating means 12 and a stack 13 for combustion gases. 'Ihe inlet 14 of the coil 10 is provided 15 with a valved pipe connection 15, whereby a regulated amount of steam may be admitted into the coil with the oil. The outlet' 16 of the coil 10 discharges into an intermediate point in a fractionating column 17, which is--provided above and below the point of entry of the pipe x16 with suitable fractionating devices, for example,

bubble cap plates 18. A perforated steam coil 19 enters the lower end of the column 17.

At its lower end the column 17 is provided with a valved outlet 20 for the withdrawal of stripped high melt-point wax. From its upper end a vapor outlet 21 leads to a partial condenser 22 of any suitable type. l-The vapor outlet 23 of the partial condenser 22 leads to a water condenser 24 provided with an outlet pipe 25. The condensate from the partial condenser 22 is withdrawn through the pipe 26 and forced by pump 27 to pipe 28 into the upper portion of the column 17. If desired, a cooling coil 28 may be provided in the topgof the column 17 for forming the necessary reiiux in the column.` Instead of returning condensate from condenser 22 for reiiux cooling, water may be supplied through line 30.

In carrying out the operation, the wax to be treated, which has previously been liquefied by suitable preheating, is forced through the coil 10, accompanied by steam supplied through the connection 15, and complete vaporization is eifected in the coil. Preferably, the wax vapors are super-heated in the coil 10 to a substantial extent, cracking being, however, avoided. The hot wax vapors and steam are discharged through the pipe 16 into the coil 17, through which the 60 wax vapors and steam rise while being sub- Jected to a substantial reux action resulting from the return of partial condensationto the pipe 26, aided, if desired, by the cooling eect of the coil 29. The condensate formed in the column descends to the lower portion thereof, and

'Ihe present invention relates to the produc-- additional steam is supplied in the column through the pipe 19.

Since the Wax is completely vaporized and preferably superheated in the coil 10, a high reiiux ratio is employed to secure the desired fractionation. The reflux ratio, produced bythe return of partial condensate through-the pipe 28 and by the cooling action'of the coil 29, and the supply of steam through the coil 19 are so controlled as to secure a condensed fraction in the lower portion of the column 17 having the ydesired high melt-point characteristics.

The uncondensed wax vapors and steam pass out of the pipe 21 into the partial condenser 22, wherein a substantially complete condensation of the wax vapors is effected. The steam together with any light uncondensed vapors pass out through the pipe 23 to the condenser coil 24. It is obvious that the partial condenser 22 may lbe replaced by any suitable form of fractionating tower in case a further fractional condensation of the vapors from the colunm 17 is desired. 'In carrying out the invention a paraffin wax or slack wax, suitably preheated to liquefy it, is forced through the coil 10 with a desired propor- 80 tion of steam. In passage through the coil, the mixture is heated to a temperature at which the Wax is completely vaporized with the proportion of steam present, and preferably is l superheated from 25 to 75. Thus the outlet 85 temperature of the coil dmay be from- 725 to 775 F. Additional steam is supplied in the column 17, serving to strip the light ends from the high melt-point wax condensate secured in this column and in addition to increase the amount of reflux cooling required in the upper portion of the column, by which increase an improved yield of the high melt-point Wax is secured. Thus it has been found that the proportion of steam used should be in excess of 1.5 lbs. per gallon of stock fed, of which from about one-eighth to about onethird may be supplied to the oil in the column 17 and the remainder in the coil. For example, in one instance the stock fed to the system was 123 F. melt-point paraiiin wax. 100 'I'he total proportion of steam supplied in the operation was 2.8 lbs. per gallon, of which about 91.5% was supplied to the oil in the coil and the remainder was supplied through. thev pipe 19in the column 17. The Asteam-wax mixture 105 was completely vaporized in the coil and brought to a temperature of 775 F. at its outlet. The vaporizingtemperature of the wax under these conditions was samewhat below 750 F. The yield of high melt-point wax secured as a con- 119 densate in the tower 17 represented about 46% of the feed and its melting-point was about 135 F. With the steam supply substantially reduced, say below 1.5 lbs. per gallon, a markedly lower yield of heavy wax distillate of the same meltpoint was secured, less than 12% being obtained.

In an operation on slack wax having a melting-point of 104 F. and containing 51% of oil, the supply of steam was controlled to give an overhead of 38.3% and a bottom of 71.7%. This bottom had a melting-point of 116.5 F. and contained less than 30% of oil. It is thus apparent that the process may be employed on crude wax or slack wax to secure a higher meltpoint product containing substantially less oil, which product may be readily sweated if desired.

Instead of using steam, a greater or less Vacuum may be employed to secure, at similar temperatures, the desired vaporization of wax, or both steam and vacuum may be employed.

High melting-point wax secured in accordance with the present invention may be readily rened, for example, by treatment with sulfuric acid, either concentrated or diluted and preferably about acid, and filtration through clay.

I claim:

1. The method of treating separated wax derived from distillate oils to secure higher meltpoint waxes therefrom, which comprises completely vaporizing the wax to be treated in the presence of steam under conditions of temperature, pressure and length of heat treatment which avoid substantial cracking and partially cooling the vapors to condense therefrom a wax having the desired characteristics.

2. The method of treating paraiiin waxes to secure higher melt-point waxes derived from distillate oils therefrom which comprises completely vapori'zing the wax to be treated in the presence of steam in a proportion exceeding 1.5 lbs. per gallon of wax treated, without substantial cracking and cooling the vapors to condense therefrom a wax product having the desired characteristics.

3. The method of treating separated wax materials to secure a higher melting-point wax therefrom which comprises completely Vaporizing such wax in the presence of steam, superheating the mixture of steam and wax vapors, and cooling the superheated vapor mixture to condense therefrom a wax product having the desired higher melting-point characteristics.

4. The method of treating separated wax derived from distillate oils to secure higher meltpoint waxes therefrom, which comprises completely vaporizing the wax without decomposition and partially cooling the vapors under subatmospheric pressure to condense therefrom a high melt wax having the desired characteristics and substantially free from low melt Wax.

5. The method of treating separated wax derived from distillate oils to produce a higher melting-point wax therefrom which comprises forcing a stream of such Wax material together with steam through a heating zone in a restricted stream, heating the mixture of oil and steam therein to secure complete vaporization of the wax slack without substantial cracking thereof, discharging the vapor mixture into an enlarged chamber, cooling the vapors in said chamber and causing the resulting condensate to descend countercurrent to the steam-vapor mixture, and controlling the cooling of said vapors tor secure a wax condensate of the desired higher melting-point characteristics.

6. The method of treating separated wax materials derived from distillate oils to produce a higher melting-point wax therefrom which comprises forcing a stream of such wax material together with steam through a heating zone in a restricted stream, heating the mixture of oil and steam therein to secure complete vaporization of the wax and to superheat the mixed vapors from 25 to 50 F., discharging the vapor mixture into an enlarged chamber, cooling the vapors in said chamber and causing the resulting condensate to descend countercurrent to the steam-vapor mixture, and controlling the cooling of said vapors to secure a wax condensate of the desired higher melting-point characteristics.

7. The method of treating separated wax materials derived from distillate oils to produce a higher melting-point wax therefrom which comprises forcing a stream of such wax material together with steam through a heating zone in a restricted stream, heating the mixture of oil and steam therein to secure complete vaporization of the wax and to superheat the vapor mixture, discharging the vaporA mixture into an enlarged chamber in which the vapors are caused to rise, cooling the rising vapors in said chamber and causing the resulting condensate to descend countercurrent to the steam-vapor mixture, separating the resulting condensate and forcing steam therethrough, admixing the resulting steam-vapor mixture with the rising mixture of superheated vapors in the enlarged chamber, and controlling the cooling of said vapors to secure a wax condensate of the desired higher melting point characteristics.

8. The method of treating separated wax derived from distillate oilsto secure higher meltpoint waxes therefrom, which comprises completely vaporizing the wax without substantial cracking thereof and partially cooling the vapors under conditions characteristic of sub-atmospheric pressure to condense therefrom a higher melting wax having the desired characteristics and substantially free from low melt WaX.

WILLIAM H. BAHLKE. 

